1. Field of the Invention
This invention relates to a method and apparatus for pipe-end shaping and welding for pipe connections and more particularly to a plurality of pins having a track on one end for forming a template for pipe end shapes or for shapes in general. The pins engage the contour of the surface to be cut or welded.
2. Description of the Related Art
In many industrial applications, such as mechanical piping, pressure vessels and steel construction, it is often necessary to join one pipe to another or to other receiving components. The pipe fitting process usually involves shape cutting of the pipe end. The cutting is always done so that the pipe end contour matches the geometry of intersection of the pipe with the other receiving component. The fabrication process may also require beveling the pipe end along the cut line in order to receive the proper welding.
The most commonly used tools for cutting and beveling pipe ends are pipe beveling machines, also known as short saddle machines. Some of the commercially available pipe beveling machines are equipped to receive shape cutting attachments known as guide templates or shape cutting attachments. These metal guide templates allow the user to cut and bevel contoured pipe ends for saddle connections such as T-joints and miter angles. Shape cutting attachments are always of cylindrical shape with one end contoured, and the other end equipped with a set of small bolting brackets. The square end is fitted to the face of the beveling machine, then the torch ruler of a short saddle machine is engaged with the contoured edge of the metal guide. With the torch ignited, the torch arm mechanism is rotated using manual or mechanical devices. A spring tension, exerted on the roller, causes the roller to follow the shaped end of the metal template, duplicating the shape of the pattern.
A pre-fabricated template is used to produce a single specific shape-cut. To cut a pipe end to take a specific contour, a specific corresponding guide template will have to be used. The fabricator can not use a pipe-beveling machine to cut or bevel pipe ends to shape, if the corresponding metal guide template is not available. This drawback limits the fabricator's options to either shape-cut pipes using a hand held torch or to keep on hand a large number of guide templates. Hand held torch cutting does not yield accurate results and usually requires additional grinding and filing. It is also very difficult to maintain a beveling angle while using a hand held torch. The process of custom making a metal guide template is complicated and involves several steps. The first step involves drawing the unfolded shape of the guide template. The next steps are marking, cutting, rolling and welding a metal sheet. The process of drawing the unfolded shape of the template requires a great deal of knowledge of descriptive geometry methods and manual or CAD drafting. Programmable pipe shape cutters are very expensive and require highly skilled workers to operate. Programmable pipe shape-cutters usually produce a limited number of standard shape cuts corresponding to commonly used pipe connections.
The prior art, involving layout of pipe connection templates, may require both joining components to be brought together and positioned at the desired orientation with respect to each other. That process requires both time and physical effort. The effort involves moving, lifting, and building temporary fixtures to hold both joining components in a specific position. It also requires tedious measuring. The larger the size of the joining components, the greater the amount of physical work involved.
Both manual and CAD drafting methods can be utilized to derive the unfolded shape of the widely used metal guide template, from the pipe connection template however this prior art is considered tedious and time consuming.